The present invention relates to the field of Data Center Systems (DCS). More specifically, it relates to a system and method for implementing a Virtual Data Center (VDC) system in a network of physical devices.
A computer network includes a plurality of network devices such as servers, firewalls, and other such appliances. Servers may be categorized as physical servers and virtual servers. Examples of physical servers include stand-alone and blade servers. Examples of virtual servers include servers created by systems that divide a physical server into one or more parts, each of which can host an independent operating environment. A server has a Network Interface Card (NIC) that connects the server to one or more Local Area Networks (LANs). The NIC has a unique Medium Access Control (MAC) address. The MAC address serves as an identifier of the server on a LAN. The present state of the art provides communications protocols, which use dynamic methods, e.g., Address Resolution Protocol (ARP), to map a higher-level identification of the server, e.g., the Internet Protocol (IP) address, as compared to the MAC address. The MAC address is used to communicate data to a server over a LAN, and is also used by some software vendors as a license key. When the NIC is changed, or the server function is moved to another server, the server loses its original MAC address-based identifier. As a result, the license may be invalidated, and the server unable to function until the network administrator manually provides a new MAC address. This often results in disruption of service.
Like an NIC, a Host Bus Adapter (HBA) connects the server to a Storage Area Network (SAN). A SAN is a network that provides access to data stored on disks or volumes, and is controlled by specialized equipment such as SAN switches and directors. Each HBA has a unique World-Wide Name (WWN), which serves as an identifier for a server on a SAN. However, if the server function moves to another server with its own HBA, or if the HBA on the server is changed, then the server may lose access to information on the SAN.
One type of information is a server image, which is required by the server to boot. The server image includes the operating system, operating system configuration data, the application software, the application configuration data, the LAN and SAN related configuration, and the LAN and SAN identities of the server. The server image required by the server may reside on a local disk of the server or on some remote storage devices. Typical examples of remote storage devices are Logical Units (LUNs) on a SAN, and a file system on Network Attached Storage (NAS) devices. NAS devices use the server's MAC address to select the server. Similarly, the SAN uses the WWN to establish a connection with the server. If the server hardware is replaced, or if the NIC or the HBA is changed, the server cannot boot without appropriate configuration changes made by the data center administrator. The process of reconfiguration is prone to errors and may result in interruption to the service, and permanent loss of critical data.
Existing methods reduce the effort and time involved in the creation and maintenance of server images by the data center administrator. However, these methods do not address the problems associated with LAN and SAN identity changes, caused by changes in the server hardware. Intervention by the data center administrator is still required, to address these problems.
Further, the servers may be organized into business systems or tiers in a DCS. Typical examples of business systems include Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), financial, trading, retail, and so forth. The servers are functionally grouped into tiers—the web tier, the application tier, the data base tier, and so forth. In the absence of a method for organizing the servers dynamically, data center administrators have to provision each tier or business system for anticipated peak utilization. This results in an exponential increase in the number of server resources, as well as in the management, and the operational cost and complexity.